Rare gene variant believed to play a role in understanding why people are left-hand dominant

What do Lady Gaga, Barack Obama, Bill Gates, Paul McCartney and Justin Bieber have in common with Ronald Reagan, Jimi Hendrix, Judy Garland, Fidel Castro and David Bowie? They are all left-handed, a trait shared by roughly 10% of people.

But why are some people left-handed while most are righties? That is an area of active research, and a new study sheds light on a genetic component of left-handedness in some people. Researchers identified rare variants of a gene involved in controlling the shape of cells and found them to be 2.7 times more common in left-handed people.

While these genetic variants account for only a tiny fraction - perhaps 0.1% - of left-handedness, the researchers said the study shows that this gene, called TUBB4B, may play a role in the development of the brain asymm...